A Brushless Direct Current (BLDC) motor has been developed to solve a problem of abrasion of a brush, which is a drawback of a DC motor. The BLDC motor has a structure in which a brush is not provided. Because the BLDC motor has improved speed and torque, high responsiveness and durability, and ability to control a rotating speed and a rotating direction, the BLDC motor is widely used in various fields including vehicles.
The BLDC motor basically has a structure in which a permanent magnet is mounted at a rotor and a coil is wound around a stator. The BLDC motor is configured to be operated by realizing and detecting a rotating state of the rotor through sensors such as a hall sensor or a photo diode and controlling a phase of a current applied to the coil in accordance with the rotating state of the rotor.
The BLDC motor has a structure in which an electrical angle is detected through sensors and the rotor is rotated by synchronizing a three-phase current or a four-phase current applied to the stator with a magnetic pole of the rotor in accordance with the electrical angle. Therefore, the BLDC motor is advantageous in that a rotating speed of the rotor is increased and noise is suppressed as mechanical friction does not occur. However, a controller inevitably needs to adjust the current being applied.
The controller is also required to be provided at a sensorless BLDC motor which detects an electrical angle with a current and a voltage detected at the motor without using sensors. The controller is configured by mounting electric circuits such as a decoder, a switching element, a current detector, a phase converter, or the like on a PCB board.
Meanwhile, as illustrated in FIG. 1, in a structure of the related art, a control board (PCB board) and a housing of a motor main body, configured as the controller, are connected by wires having ends to which connecters are connected.
That is, in order to allow currents to flow into the coil wound around the stator to drive the rotor, three wires (four wires in a case of a four-phase motor) are needed to apply currents which have phase difference. In addition, three hall sensors, which are disposed at intervals of 120° to detect a position of the rotor, each require objects to carry out the detection. Thus, total five wires for signals including a pair of + and − additional power lines are required for the three hall sensors to be operated.
Therefore, at least eight strands of wires are required between the housing and the control board.
A structure of the related art also requires, in addition to the aforementioned wires, a pair of connectors that are mounted at ends of each of the wires to be electrically connected to the main body and the control board. Further, a process of connecting the connectors is performed by a manual work through labor. Therefore, the structure of the related art has a problem in that an additional work space is needed and process time for manufacturing and assembling processes increases. Thus, it has limitations in miniaturizing products and reducing unit costs.